Testing the new generation of anchors

28 Mar 2014

Tired of less than comprehensive overseas tests, Jon Neeves organises his own tests and puts a batch of old favourites and new-generation anchors through their paces.

It appears that yachting magazines publish anchor surveys about every two years — anything more frequent and the reader’s eyes glaze over. This is a slightly different anchor article, looking at other aspects of performance.

Anchor articles in the past have tried to educate us with the superior holding capacity of some of the newer anchors. Interestingly the message has been largely missed because most yachts are still decorated with anchors designed and introduced 40 years ago! Anchor choice is not a cost issue (except for some boat builders and dealers) — because some old-style anchors are more expensive than the newer more efficient models.

Testing

Testing is commonly conducted using a large work boat with 350hp-500hp engines or a shore-based high-powered winch, minimum capacity 2T but typically 5T. Testing is conducted under water and the anchor is set at a fixed rode ratio, commonly 5:1 but up to 10:1 using a chain sized to suit the anchor. The anchors tested are commonly in the 10kg-20kg range. They are set by simply dragging them until such time that the anchor drags at a steady rate. The load needed to pull the anchor is termed “holding capacity”.

People have become fixated with holding capacity and ignored other features. Another flaw is that some anchor makers only provide a specially selected anchor for test, with a sharp toe and perfect balance etc, which is not necessarily typical of the anchor you find in your local chandlery.

Sadly, the tests do not really simulate the way we anchor and the biggest fault is the sensitivity. It’s actually almost impossible to set a CQR at a 5:1 (and worse 10:1) scope when the yacht is being driven (or dragging) determinedly. The same problem occurs with Bruce-type anchors on firm substrates. Pull them with a potential load of 5T and if a Bruce even starts to set the setting load is so powerful they will immediately be pulled out of the small patch where setting might have been possible.

The other problem is one pull of an anchor in one seabed. Statistically the minimalist results have little credibility because seabeds vary. There are better ways to test, but they are even more expensive because they involve measuring loads just prior to movement, i.e. a static maximum load, and it can take all day just to test one anchor with three pulls. It is virtually impossible to measure maximum static loads from a work boat. Fortunately, we now have a decent cross-section of test results (and some tests are a bit more exhaustive) and a semblance of a pattern is discernable.

What you can ascertain from the results

Looking at the results we have a group of anchors — call them “old generation,” the CQR, Delta, and Bruce — that might have a holding capacity of 750kg for a 15kg anchor set properly in a good holding seabed. We have another group of anchors, the “new generation,” Fortress, Spade, Super SARCA, SARCA Excel, Manson Supreme and Kobra — that have a holding capacity of 1500kg for the same weighted 15kg anchor. A 15kg anchor might be of the size specified for a 35’-40’ yacht. There might be differences in these groupings. A Supreme might be better than a Spade (or vice-versa) but the differences are small, say 10 percent. The obvious question is: what do these holding capacity figures mean? After all a 750kg holding capacity anchor for a 35’ yacht weighing in at 6T looks pretty good.

Our testing

We took Josepheline, our Lightwave 10.5 (35’ — but now extended to 38’), and measured the load on the anchor chain at different scope ratios during a developing summer seabreeze. We chose Pittwater as our location, off Barrenjoey Beach. The water is around three metres deep and the seabed is flat and composed of weed with clean sand patches. We fixed a location with GPS and anchored in the sand patches. The location is largely protected by Barrenjoey headland and wave development is minimal, typically less than 0.3m. We dispensed with our bridle and measured the load directly on the anchor chain using a load cell with the other end of the load cell fixed with Dyneema through the block on the self-tacking track to a mast located winch. Wind speeds, from five knots to 35 knots, were measured from our masthead wind gear. We did check that our anchor, an Anchor Right 16kg SARCA Excel, remained in the same place during the tests; any movement would reduce the loads recorded.

Most people do not have a catamaran and we measured the windage of our Lightwave and compared it to both a Bavaria 35 and Bavaria 45. Measurements, or areas, were based on manufacturer’s drawings. We simply took maximum bow on and side surface areas, added them together and compared. Our Lightwave has approximately the same surface area, or windage (ignoring any streamlining) as the Bavaria 45 (we cheated slightly and assumed masts, booms and sails were common to both). The two yachts obviously have different underwater profiles and weights but the surface areas, or windage, are similar. The Bavaria 45 and Lightwave have a windage 30 percent greater than the smaller Bavaria 35.

What we found was that maximum loads developed at short scopes (but we all knew that) but at slightly less than a 3:1 scope the maximum load recorded was 650kg. Cross referring back to those holding capacity figures — an old-generation anchor would be working at the limit of its safe performance but the new generation anchor would have a factor of safety of two times. Now — not many of us are going to anchor at a 3:1 scope in a 35-knot wind — but sometimes we will anchor in less good holding seabeds, so the figures might raise some questions in some owners’ minds as to the effectiveness of their anchors.

Snatch loads

However, the other factor we identified was that anchor holding capacity is measured with a steady load but all of the anchor loads we measured were snatch loads (dynamic loads) with short, sharp impacts. The other factor was that Josepheline yawed about her anchor, swinging to left and right and it was this veering and yawing that led to the impact load. Because of wind shear, gusts or bullets blowing at an angle to the average wind direction, Josepheline would swing to one side and then could be buffeted by a gust from, basically, 90 degrees. It was the constant switching of the wind, more severe at higher wind speeds, that caused the snatch loads.

We cannot comment on the difference between say a sustained load of 500kg and a short but sharply impacted load of 500kg on a well set anchor. One might think that the sustained load could allow the anchor to pull through the seabed but the snatch load simply jerk it out (and maybe not allow it to re-set). Possibly future tests might resolve this issue (if we can find a way of safely snatch loading a pre-set anchor). Advantageously snatch loads can be managed, sustained loads less easily minimised (two anchors set at 90 degrees to each other, difficult on a cold, dark, wet stormy night). You can obviously increase the amount of chain deployed, but you have a finite amount of chain and might not have swing room to deploy what you want.

A key to reducing the impact of a snatch load is elasticity. Imagine a bungy jumper leaping off one of those NZ bridges with their ankles secured to a long elastic cord. The jumper once reaching the end of his tether feels almost nothing, except relief. All of the momentum of the fall is absorbed by the elastic cord. Introduce something similar to your anchor rode and you will achieve the same sort of effect.

Snubbers

The best and most economical mechanism is to install a decent snubber. Some, surprisingly few, use snubbers but only to take the load off the anchor windlass. If you extend the snubber, you can employ the elasticity of the line as your own anchor bungy. Nylon, and other synthetic fibre, has an elasticity of about 20 or up to 30 percent (do not use Dyneema because it has no stretch at all). If you take a length of nylon, an old double-braid halyard or sheet will suffice, and run it from stern to bow you will have a roughly boat-length snubber. You could go off and buy anchorplait, but recycling old running rigging seems sensible. Historically hawser laid, as opposed to braided rope, was meant to be more elastic (because of the method of construction), but we can find no modern reference.

We attach our snubber to the stern horn cleats and run it through the slots at the base of our stanchions, through turning blocks on the bow and to a chain hook. Because we have a catamaran we have two such lines, one up each sidedeck, and the same system could be employed for a beamy monohull but one line up one sidedeck would suffice for a smaller yacht. For a 35’ yacht 10mm double braid would be adequate; much thinner and it will wear too quickly (but give more elasticity) and much thicker and the loads necessary for stretch will not develop. Monohulls should not need turning blocks. Simply run through a fairlead or the bow roller, and we use clear plastic hosepipe for areas of potential wear. For a 35’ yacht you will finish with 12m of nylon you can extend beyond the bow, which will give you a usable one metre of elasticity (you should not experience loads sufficiently high to use the rest of the elasticity). In practice — if you have a snatch load, some might be taken up as the chain lifts completely. Some or most of the rest is taken by the snubber stretching.

An alternative we have seen is 4WD snatch retrieval tape. We have seen it used only in short lengths, as a bridle, but it might be possible to arrange longer runs and then enjoy more elasticity. It comes, possibly inconveniently, as a 50mm-wide tape but is designed specifically as a snatch cord and looks ideal, if you can find a way to install it sensibly. You do need the length.

There are commercially available devices, usually rubber, that purport to achieve the same effect as the nylon snubber rope. Sadly many (all) of these snubber devices do not work at high loads. Simplistically, they break, and it’s actually at high loads that you need performance. A company in America produces devices called “Shockles” claimed to have been designed as anchor snubbers. They look interesting but are not easily available (you need to order direct from America), and we have been unable to find tests conducted at high loads.

We have used our nylon rope snubbers and have not measured loads in excess of 100kg on the stern cleats. There are considerable friction losses, which help, but 100kg loads are considerably less than 650kg. An advantage of having two snubber lines, down each sidedeck, is that it helps centre the yacht, more evident on a multihull than a monohull, but it also spreads the load. We find as Josepheline veers first in one then the other direction the snubber takes the load, rather than the load always being on one rope. We leave our snubber lines permanently attached, which clogs the aft horn cleat a bit and if it were an issue we might install dedicated horn cleats or padeyes.

One way to reduce yawing is to deploy a second anchor off the bow. If you were to use two similarly sized anchors, this will almost double the holding capacity. Ideally you want to set the two rodes at about 90 degrees to each other. We find the best method of deployment is set the first anchor as usual and deploy the second one from the dinghy. Josepheline’s second anchor has 30m of chain and 40m of 12mm hawser-laid nylon (so it incorporates its own snubber). Deploying a 16kg anchor and 30m of chain from a dinghy has its own problems (primarily weight), and we have focussed on using a 7kg alloy Spade, the A80 (that has a similar holding capacity to our Excel). Two anchors deployed from the bow would be less than ideal if you are expecting big wind or tide changes.

Poll of yacht owners

A subjective poll was conducted of owners and though many suggested they were interested in holding capacity (and presumably high holding capacity) they were more interested in anchors that also worked in a wide cross-section of seabeds and anchors that could cope with wind and tide changes. There might be a suggestion that some holding capacity would be sacrificed for an ability to be dependable in a variety of seabeds and able to accommodate wind and tide changes.

If you want to read up on anchor testing, then the best compilation of easily accessible anchor tests as PDF versions is found on www.mansonanchors.com but most anchor makers have published anchor tests on their websites. They might not be edited but they, unsurprisingly, tend to use articles favourable to their product. If you want to learn more about how classification societies test anchors there is a short description within www.iacs.org.uk For Shockles go to www.shockles.com

Choosing an anchor that will not toss and turn

On our Lightwave 10.5 we use a 16kg SARCA Excel with 8mm chain as our primary anchor and a Spade, alloy, A80 as a secondary anchor. It depends where we are cruising, but we might also carry a further 13kg Excel. This combination has proven exceptional.

We anchor in some locations that can be taxing but neighbouring yachts in the same anchorages commonly employ different anchors including Bruce types (we test the Claw and the Ray here), CQRs, Deltas and Manson Supremes and the owners seem equally happy. Our anchor choice was based on what we thought was the best — but presumably their anchor choice was also their best and maybe their anchors were lighter, or heavier, than recommended — it would not do if we were all the same.

In this section we look at the ability of anchors to set and re-set in different seabeds — trying to simulate changes in wind and tide. Simplistically, we set a range of anchors, in the 5kg to 10kg range, then subjected them to pulls of 90 degrees to the setting direction and 180 degrees to the setting direction. We conducted the tests in different seabeds using different loading techniques. We used a small runabout with a 60hp engine to set anchors at about 90kg setting load. We then pulled them at 90 degrees to the setting direction and 180 degrees to the setting direction (causing the anchors to somersault). A 90kg load is slightly more than the load developed if you set an anchor with 50m of 8mm chain in three metres of water and reverse the yacht to just lift all the chain off the seabed. We repeated the tests with a beach-based winch (speed of 0.3kn, max capacity 5T), setting the anchors to 200kg then moving the winch so as to load them at 90 degrees to the original setting direction. 200kg is the maximum snatch load developed in 25-knot winds with 40m of chain and a 10:1 scope. We did a simple set and lift test using Josepheline in a glutinous seamud to test for mud retention and finally we conducted a further beach test where we set and then re-set at 180 degrees.

The original idea was to test using Josepheline — but this was inordinately difficult. The other test we attempted was in weed. In heavy weed the only anchor we could get to set was the Super SARCA, but it would not re-set. In lighter weed the Manson Supreme set easily — but we found it difficult to locate enough light weed seabed of the same characteristics to test all the anchors so abandoned this phase.

Our winch tests were conducted on a hard granitic sand, in the intertidal area. We were unable to set the Manson Ray, Lewmar Claw, fisherman, Cooper nor CQR. In sand, where we did the runabout testing, we still could not set the Cooper, the fisherman never set deeply and had no holding capacity and the CQR never re-set (the scope was too long). The fisherman would not set in the heavy weed. Based on this we abandoned any detailed work on the CQR, Cooper and fisherman. But in sand the Claw and Ray performed well and set easily in the mud test.

First test

Our first test, very subjective, was to set each anchor and then find at what point the anchor would stop swivelling in the sand and be forced to somersault. We did this by hand. Simply set the anchor with two of us pulling on the chain/rope rode and then walking round and find at what angle the anchors dragged and somersaulted. For most anchors this occurred at about 150 degrees. We did not employ a sharp pull, simply developed a load slowly to identify when the anchor moved. The exception was the Super SARCA, which did not somersault as such, but at about 120 degrees the trip release operated as designed, the anchor pulled out backwards, turned over, and re-set. The Super SARCA operates exactly as it is designed to do but does this 30 degrees earlier than other anchors will drag/somersault (and considering the care you take to set the anchor originally this ease of self-tripping might not be advantageous). However, this is not a major issue. It is possible to lock the shackle at the end of the shank using a nyloc nut and bolt and the Super SARCA then performs exactly the same way as any other anchor. In real life if you think you need the trip release, say anchoring in the reef, then simply loosen the nyloc nut, slide it forward and tighten. In our test programme the Super SARCA was tested with the bolt installed to stop self-tripping except for one 180-degree test with the winch. The best-performing anchors in this swivelling test were the Spade, Ultra and Kobra — all of which have protruding soles. Whether better swivelling is engendered because of the protuberance or because the centre of gravity is lower and nearer the toe remains unknown. The interface angle, between sliding or swivelling round and somersaulting, of 150 degrees might be seabed type dependent — we did not check, but it merits some further examination.

The 90-degree turns, winch/beach or runabout testing all returned the same results. Testing was conducted at 10:1 scope for the winch test and 10:1 for the runabout test. Most anchors, excluding the CQR, simply swivelled in the seabed and re-aligned to the new direction of load. The CQR dragged and would not re-set. There were differences with the other anchors but they might be attributed to limitations of the test technique. They were not that significant and could be due to variations in seabed rather than differences in anchor performance.

Again the best performing anchors at 90 degrees were the Kobra, Ultra and Spade but their better performance was not factorially outstanding in comparison with the Delta, Ray, Claw, Super SARCA, SARCA Excel, Supreme and Rocna (we only tested the Rocna with the winch). Basically all anchors have the ability to remain set but swivel in the seabed, both a good sand (ideal for anchoring) and in a hard granitic sand. We did the 90-degree tests with the runabout 3-4 times for each anchor but also used the same technique to test for an ability to reset in a 180-degree turn (two pulls). Basically we drove over the anchor simulating a change in tide or big wind shift. Again all the anchors performed well. They “somersaulted” cleanly and immediately re-set. The only exception was the Claw that on two occasions would not re-set, it simply skated over the sand — but we tested it again on another day, same location and it re-set at 180 degrees without problem. All of the anchors set well initially and then re-set at 180 degrees almost as quickly.

We did the same 90-degree winch test, under water in the intertidal zone, and achieved the same results, except the CQR, Claw, Ray, fisherman and Cooper which did not set at all. Though the sand is hard, which is part of the reason why some anchors did not set, those that did set performed as we had found with the runabout test. Anchors simply swivelled and remained set. Again there was no stand-out winners, except the Spade, Ultra and Kobra were better.

Soft mud

We then looked at the ability to retain seabed in a soft mud. The tests were conducted from Josepheline in Little Pittwater. The seabed is a soft glutinous mud with bits of decaying twigs and small shells. All the anchors were set to the same load with the same scope (4:1, all chain) at the same depth; we simply changed location slightly. The test was a simple set and lift, using photography to record results. For comparison we have some images of actual anchors having been similarly used to underline that the results are not posed. On retrieval all of the convex anchors, Kobra, SARCA Excel, Delta, Super SARCA all came up clean. The pronounced concave anchors came up with a considerable amounts of mud, being the Supreme, Ray and Claw. The two shallow concave anchors performed slightly differently, the Spade was clean, the Ultra carried some mud. This latter was a surprise because it had been thought the two anchors would perform similarly and the stainless Ultra would be self-cleaning. In all cases the chain was very muddy — and a deck wash essential, even if only for the chain. The fact that the concave anchors held mud did not in any way impact their ability to set; all anchors set well.

180-degree-turn test

The final test was our winch/beach 180-degree turn test. We set it up by first setting two large anchors under high load and attaching snatch blocks to each anchor. The anchors were set in water about 100m apart. Using a very long length of wire cable we were able to pull each anchor first toward one winch, then re-set and pull toward the other winch (along the 100m corridor between the two large anchors). The anchors under test were set to 200kg then forced to somersault until re-set to 200kg. We set the two turning anchors with the snatch blocks far apart to ensure each anchor could be tested “down the corridor” in undisturbed seabed. The test was inordinately slow (because we actually only had one snatch block and not enough cable, so needed to drag snatch block and cable about for each pull) and we only managed one pull for each anchor, although we found some anomalous results and did test some anchors twice.

We tested the Kobra, Spade, Super SARCA, SARCA Excel, Supreme, Delta, Rocna and Ultra. This test illustrated the problems identified in the mud retention tests. The convex anchors, Delta, Super SARCA, SARCA Excel and Kobra (and the slightly concave Spade) all somersaulted, breaking out of the seabed clean and immediately re-setting to 200kg. Basically there were no performance differences. We did test the Super SARCA again, without the bolt so that it could self-trip, but it performed less well in this mode, taking further from its initial set position to a fully re-set position. This is because it trips and drags in the tripped mode before reversing and allowing the shackle to slide to the shank end. The other convex anchors simply somersault and immediately commence to re-set.

The concave anchors, the Supreme and Rocna, performed differently. When they somersaulted the flukes of both were full of impacted seabed. They dragged with their shanks half-buried, fluke to the top, slowly shedding this seabed and it was not until almost clean and the shanks surfaced from the half-buried position that they rolled over and were able to re-set. Subjectively they dragged for 50 percent further than the convex anchors before re-setting. Again the Ultra carried seabed, not much and not enough to affect performance — but enough to raise a minor question.

Conclusions

All anchors are a compromise. In sand all anchors perform well excepting the Cooper that we could not get to set at all, the fisherman which had no capacity (and would not even set in weed) and CQR, which has difficulty re-setting when subjected to change in load orientation. Of the rest in sand all anchors set well and had the ability to reorientate to a change of load direction of both 90 and 180 degrees. There seemed little difference in performance although the anchors with protruding soles, the Kobra, Spade and Ultra, seemed to perform better in the 90-degree turns. The major difference is holding capacity and if you are to anchor under arduous conditions an anchor with higher holding capacity like the Kobra, Spade, Ultra, Supreme, Rocna and the two SARCAs looks the better option. In hard seabeds there might be question marks over the Ray and Claw which with care you might get to set, but might not re-set if forced to re-orientate through 180 degrees but on balance the Ray seemed to perform better — though both do not have high holding capacity. In seabeds capable of high compaction then the concave anchors perform well in 90 degree turns but might have choked and be unable to re-set if forced into a 180-degree turn.

Anchors are a very personal choice and owners buy for reasons that are sometimes ill defined. But for those whose preference lies to a concave design the Supreme looks a good all-round performer and is backed by Lloyds Register certification. For those who are part of the “plough” camp, of the convex anchors the Delta is an adequate performer, but low holding capacity, and the Kobra and two SARCAs look a better bet. The Super SARCA and SARCA Excel also enjoy accreditation from Australia’s National Marine Safety Committee. The Kobra works very well but must remain on the sidelines — if only because the shank seems a bit flimsy and no detail is given of shank construction (both the Supreme and Excel are engineered from high-tensile steel of declared quality).

The shallow concave anchors, the Spade and Ultra, are both outstanding performers and are both outstandingly expensive. Sadly given that price is part of the decision-making process then the best buys would be the Supreme, for the concave converts and the Excel for the plough diehards. The Super SARCA is a good performer but offers little advantage to a yachtsman over its younger brother, the Excel, unless you anchor in the reef frequently (and you should not be anchoring in coral anyway). But if you have an old-style anchor and do not intend anchoring under arduous conditions then simply incorporate a proper snubber because this will be a major addition to your ground tackle.

We did not test “all” anchors, and there are some quality anchors we missed. We would highlight the Fortress (which has an excellent reputation in America and is very popular). We have also not tested Manson’s Racer, another alloy “sand” anchor nor Wasi’s Bugel or XYZ. We have also not tested the plethora of unbranded copy anchors — the manufacturing technique and raw materials for which might be queried.

We have attempted to extend anchor testing slightly beyond “holding capacity” but do not claim a high degree of statistical excellence. It is a first attempt at extending the parameters available to the yacht owner. We have mentioned an inability to measure snatch loads on a set anchor. Our 90 and 180-degree re-setting tests require repetition by other workers in different seabeds. Some test procedures need be developed to look at the impact of waves. The more we learn the more there seems to be to find out.

THE ANCHORS WE TESTED

The anchors tested in this survey were largely lent by the anchor manufacturers themselves and thanks are extended to Barlow who provided the Lewmar models Delta and Claw, Ultra in Brisbane, Manson who lent both the Supreme and Ray, Anchor Right who provided the small Excel. We already owned the CQR and borrowed our son’s Super SARCA. Rocna were unable to lend one of their new Chinese models, and we borrowed an original NZ model for some of the testing. Spade provided the small steel Spade and the larger alloy version. Cooper had already submitted their model for testing for “The Ideas Locker”. We had purchased the Kobra on our last visit to the UK and brought it back as checked in luggage and the fishermans we purchased from the secondhand boat-part shop, The Bosun’s Locker, in Warriewood, Sydney. In the future we hope to extend the investigation and include the Fortress and Manson’s alloy Racer. Some of the anchor makers allowed us to decorate their models with bright paint to enhance opportunity for photography — we are not aware that it alters performance.

WHERE TO BUY THEM

Most good anchors can be purchased from chandlers in Australia. Sadly chandlers do not stock all sizes, nor all anchors, but they do stock unbranded anchors that should be avoided at all costs.

• Spade anchors have no distributor in Australia, but Spade will deliver here by sea-freight — at www.spade-anchor.com

• Kobra, this anchor is part of the Plastimo range who are represented here by RFD. RFD do not import anchors, nor much else of the Plastimo range but might be persuaded to add an anchor to one of their shipments.

• Cooper — contact the manufacturer direct. They offer only an emailaddress on their website — sales@cooperanchors.com.au

Probably the largest range of anchors available in the southern hemisphere including Manson, Anchor Right, Spade and many others are in stock at Chains, Ropes and Anchors in New Zealand, ph (64) 9 444 8212. They will ship to Australia.